This application is based on and claims priority from Japanese Patent Application No. 2001-308680 filed on Oct. 4, 2001, the content of which is incorporated herein by reference.
1. Field of the Invention
The present invention relates to a balance weight used for a wheel of a two-wheel vehicle.
2. Description of the Related Art
Usually, a balance weight is mounted on a wheel of a two-wheel vehicle for removing a rotational imbalance of the wheel.
A conventional balance weight for a wheel of a two-wheel vehicle includes a weight body made from lead and made in the form of a bar and a clip having one end embedded in the weight body. The balance weight is fixed to the wheel by attaching the clip to a rib of a wheel rim of the wheel.
The weight body is a cast of lead. The clip is made from spring-steel having elasticity. The clip is fixed to the weight body by embedding one end of the clip in the weight body during casting of the weight body. In order to provide the clip with a spring-elasticity, the clip is heat-treated before the one end of the clip is embedded in the weight body. Since the melting point of lead is lower than the heat-treatment temperature of the clip, the spring elasticity of the clip is not lost during casting of the weight body with the one end of the clip in the weight body.
However, the conventional balance weight for a wheel of a two-wheel vehicle has an environmental problem because the weight body is made from lead.
Replacement to metal other than lead could be conceived. For example, iron and steel are safe from the viewpoint of the environment and are relatively cheap, and have a relatively high specific density.
However, use of those metals is accompanied by a problem that the spring-elasticity of the clip is lowered, because the melting points of the clip and the weight body of iron or steel are close to each other and an alloy-phase and a heat-affected zone are formed in the clip during casting of the weight body with one end of the clip in the weight body. If the heat-treatment of the clip is attempted to be conducted after the casting of the weight body, the heat-treatment conditions of the clip are very difficult to be selected and, as a result, the heat-treatment of the clip is accompanied by an increase in cost, because the clip and the weight body are integral with each other.
An object of the present invention is to provide a balance weight for a wheel of a two-wheel vehicle capable of changing a material of a weight body to metal other than lead and capable of maintaining a spring-elasticity of a clip as high as that of a clip of a conventional balance weight with a lead weight body.
A balance weight for a wheel of a two-wheel vehicle according to the present invention includes a weight body made from metal other than lead and a clip made from spring-steel.
The weight body has a transverse cross-section of the form of U-letter and a groove for mounting the clip therein. The weight body includes a groove bottom wall and a pair of groove side walls connected to opposite width ends of the groove bottom wall.
The clip includes a bottom portion and a pair of arms connected to opposite width ends of the bottom portion of the clip. Each of the pair of arms includes a first, inclining portion extending toward an opposite arm of the pair of arms and in a direction away from the bottom portion of the clip, a second, rib-holding portion connected to the first portion and located closest to the opposite arm of the pair of arms, and a third, guide portion connected to the second portion and extending in a direction away from the opposite arm of the pair of arms and in the direction away from the bottom portion of the clip.
The clip is mounted to the groove bottom wall of the weight body with the bottom portion of the clip contacting closely to the groove bottom wall of the weight body, and the clip is fixed to the groove bottom wall of the weight body at the bottom portion of the clip.
The weight body is made from iron, for example, cast iron and cast steel.
The weight body may have a protrusion for coupling the clip, at the groove bottom wall of the weight body, and the clip may have an aperture formed in the bottom portion of the clip. The clip and the weight body may be coupled to each other by inserting the protrusion of the weight body into the aperture of the clip and then caulking the protrusion.
The coupling may be achieved by spot-welding or projection-welding.
The balance weight is mounted to a wheel rim of the wheel of a two-wheel vehicle by inserting a rib of the wheel rim into the clip of the balance weight. The pair of arms of the clip hold the rib between them due to the spring-elasticity of the clip and is fixed to the rib. Since the balance weight can be mounted only by inserting the rib into the clip, the mounting of the balance weight to the wheel is easy.
Since the weight body is made from metal other than lead, the environmental problem existing in the conventional balance weight having a lead weight body is removed. In the case where the weight body is made from iron, for example, ductile cast iron or cast steel, a sufficient amount of weight is assured even by a weight body of a relatively small size, so that a balance weight of a low cost is provided.
In the case where the weight body is made from ductile cast iron or cast steel, the weight body can be coupled with the clip by various methods, such as caulking, spot-welding, and projection-welding. Therefore, the spring-elasticity of the clip is not lowered.